Checklist Topic 10 Ecology and Human Influences on the Environment (exams 2025) Extended
Energy Flow
State that the Sun is the principal source of energy input to biological systems
Describe the flow of energy through living organisms, including light energy from the Sun and chemical energy in organisms, and its eventual transfer to the environment
Food Chains and Food Webs
Describe a food chain as showing the transfer of energy from one organism to the next, beginning with a producer
Construct and interpret simple food chains
Describe a food web as a network of interconnected food chains and interpret food webs
Describe a producer as an organism that makes its own organic nutrients, usually using energy from sunlight, through photosynthesis
Describe a consumer as an organism that gets its energy by feeding on other organisms
State that consumers may be classed as primary, secondary and tertiary according to their position in a food chain
Describe a herbivore as an animal that gets its energy by eating plants
Describe a carnivore as an animal that gets its energy by eating other animals
Describe a decomposer as an organism that gets its energy from dead or waste organic material
Use food chains and food webs to describe the impact humans have through overharvesting of food species and through introducing foreign species to a habitat
Describe a trophic level as the position of an organism in a food chain and food web
Identify the following as the trophic levels in food webs and food chains: producers, primary consumers, secondary consumers, tertiary consumers and quaternary consumers
Explain why the transfer of energy from one trophic level to another is often not efficient
Explain, in terms of energy loss, why food chains usually have fewer than five trophic levels
Explain why it is more energy efficient for humans to eat crop plants than to eat livestock that have been fed on crop plants
Carbon Cycle
Describe the carbon cycle, limited to: photosynthesis, respiration, feeding, decomposition, formation of fossil fuels and combustion
Human influences on ecosystems
Describe an ecosystem as a unit containing the community of organisms and their environment, interacting together
Describe biodiversity as the number of different species that live in an area
"Describe the reasons for habitat destruction,
including:
(a) increased area for housing, crop plant production and livestock production
(b) extraction of natural resources
(c) freshwater and marine pollution (a detailed description of eutrophication is not required)"
State the undesirable effects of deforestation as an example of habitat destruction, to include: reducing biodiversity, extinction, loss of soil, flooding and increase of carbon dioxide in the atmosphere
Explain the undesirable effects of deforestation as an example of habitat destruction, to include: reducing biodiversity, extinction, loss of soil, flooding and increase of carbon dioxide in the atmosphere
Conservation
Explain why organisms become endangered or extinct, including: climate change, habitat destruction, hunting, overharvesting, pollution and introduced species
"Describe how endangered species can be conserved, limited to:
(a) monitoring and protecting species and habitats
(b) education
(c) captive breeding programmes
(d) seed banks" | Chalk